Improve resource load cache

-Added a new method in Resource: reset_state , used for reloading the same resource from disk
-Added a new cache mode "replace" in ResourceLoader, which reuses existing loaded sub-resources but resets their data from disk (or replaces them if they chaged type)
-Because the correct sub-resource paths are always loaded now, this fixes bugs with subresource folding or subresource ordering when saving.

1 files changed, 2 insertions, 0 deletions

diff --git a/core/io/resource.h b/core/io/resource.h
index d0cd6ea3ac..ae18ac0c8a 100644
--- a/core/io/resource.h
+++ b/core/io/resource.h
@@ -90,6 +90,8 @@ public:
 	static Node *(*_get_local_scene_func)(); //used by editor
 
 	virtual bool editor_can_reload_from_file();
+	virtual void reset_state(); //for resources that use variable amount of properties, either via _validate_property or _get_property_list, this function needs to be implemented to correctly clear state
+	virtual Error copy_from(const Ref<Resource> &p_resource);
 	virtual void reload_from_file();
 
 	void register_owner(Object *p_owner);